132 THE ANTERIOR CRANIAL NERVES 



one of its branches (a) is distributed. Branch (6) of the 

 nasalis branches outwardly and distributes itself to the 

 integument of the side of the upper jaw. Shortly after 

 the nasalis has divided from the maxillaris, a large branch 

 (c) splits off with the following course and distribution : 

 The nerve turns sharply inward and passes over the ol- 

 factory nerve to which it gives off a small branch. Thence 

 its course is downward and forward near the roof of the 

 mouth to the snout, passing downward through the pre- 

 maxillary bone for distribution to the region of the upper 

 lip. 



There arises from the supramaxillaris, superior soon 

 after leaving the Gasserian ganglion, a nerve which follows 

 along near its parent until it reaches the orbit in which it 

 bends upward and outward. Then it leaves the orbit and 

 turns upward, backward and inward, distributing itself to 

 the cutaneous layer on the top of the head midway be- 

 tween the eyes. This nerve is apparently the same as that 

 which Fischer has described in the case of Necturus, as 

 innervating the skin of the dorsal surface of the head. 

 According to Huxley (Encyl. Brit., Art. Amphibia), it 

 occurs only in the tadpole of An lira and disappears from 

 the adult. 



From the maxillaris superior, there also arises a nerve 

 which innervates the superior oblique eye muscle and 

 hence is to be regarded as trochlearis which has remained 

 fused with the fifth, a condition possessing much morpho- 

 logical interest. 



The oculomotor nerve (o.c.m.) arises the ventral side 

 of the medulla oblongata. Its course is outward and for- 

 ward within the chondrocranium, then it leaves the chon- 

 drocranium through the same foramen as the trigeminal 

 and runs forward to be distributed in the usual manner to 

 the rectus muscles of the eye. The only feature worthy of 



